Selection of a manipulator configuration during off-line path planning in Point-to-Point positioning

Abstract

The paper concerns a problem of a robotic manipulator configuration selection during off-line programing of the robot operation. The path-planning task was considered. It was assumed that the path was static and it was determined basing on geometry of a considered operation. The analysis was limited to the Point-to-Point positioning mode, and it was carried out for a 6R manipulator structure. Solution of the inverse kinematic problem of such the manipulator leads to 8 solutions. Each of them, if available, might be selected as the configuration of the manipulator at a node of the path. For a set of many nodal points this provides a great variety of possible paths with various configurations chosen at the nodes along the path. The authors suggested determination of the planned paths’ lengths, and selection of the shortest paths as the most appropriate for application. The numerical analysis is presented for 2 exemplary paths. Total displacements in joints corresponding to motion along the determined paths were used for assessment of the obtained results, which confirmed that the selection of the shortest path provides useful and applicable solution for path-planning, especially for long-range PTP motions and for PTP paths whose consequent nodal points’ orientation varies considerably.